Distributed Sensing Technique for Large-Scale Composite Structures with Embedded Small-Diameter Optical Fibers

2006 ◽  
Author(s):  
Tadahito Mizutani ◽  
Takafumi Nishi ◽  
Nobuo Takeda
Keyword(s):  
Optical Fibers ◽  
Composite Structures ◽  
Large Scale ◽  
Small Diameter ◽  
Distributed Sensing

Distributed Fiber Optic Strain Sensing with Embedded Small-Diameter Optical Fibers in CFRP Laminate

2007 ◽  
Vol 334-335 ◽  
pp. 1013-1016
Author(s):  
Tadahito Mizutani ◽  
Takafumi Nishi ◽  
Nobuo Takeda
Keyword(s):  
Spatial Resolution ◽  
Optical Fibers ◽  
Composite Structures ◽  
Fiber Optic ◽  
Current Trend ◽  
Small Diameter ◽  
Long Distance ◽  
Distributed Sensors ◽  
Cfrp Laminate ◽  
Sensing Applications

Although demand for composite structures rapidly increase due to the advantages in weight, there are few effective assessment techniques to enable the quality control and guarantee the durability. In particular, an invisible microscopic damage detection technology is highly required because damages such as transverse cracks, debondings, or delaminations can lead to the critical failure of the structures. Among many non-destructive evaluation (NDE) methods for composite structures, fiber optic sensors are especially attractive due to the high sensitivity, the lightweight, and the small size. In the current trend of the structural health monitoring technology, fiber Bragg gratings (FBG) sensors are frequently used as strain or temperature sensors, and Brillouin scattering sensors are also often used for a long distance distributed measurement. The Brillouin distributed sensors can measure strain over a distance of 10km while a spatial resolution was limited to 1m. Some novel sensing method is proposed to improve the spatial resolution. The pulse-prepump Brillouin optical time domain analysis (PPP-BOTDA) is one of the latest distributed sensing applications with a cm-order high spatial resolution. The PPP-BOTDA commercial product has the spatial resolution of 10cm, and can measure the strain with a precision of ±25og. This precision, however, can be achieved by using conventional single-mode optical fibers. In our research, small-diameter optical fibers with a cladding diameter of 40om were embedded in the CFRP laminate to avoid the deterioration of the CFRP mechanical properties. Thus, in order to verify the performance of PPP-BOTDA, the distributed strain measurement was conducted with the small-diameter optical fibers embedded in the CFRP laminate.

Distributed Strain Monitoring for Damage Evolution in CFRP Bolted Structures with Embedded Optical Fibers

2013 ◽  
Vol 558 ◽  
pp. 252-259 ◽  
Author(s):  
Nobuo Takeda ◽  
Shu Minakuchi ◽  
Takeyuki Nadabe
Keyword(s):  
Optical Fibers ◽  
Composite Structures ◽  
Large Scale ◽  
Permanent Deformation ◽  
Bolted Joints ◽  
Element Analysis ◽  
Internal Damage ◽  
Aerospace Applications ◽  
Strain Change ◽  
Distributed Strain

The authors proposed fiber-optic-based damage monitoring of carbon fiber reinforced plastic (CFRP) bolted joints. Optical fibers were embedded along bolt holes and strain change along the optical fiber induced by internal damage was measured by a Brillouin Optical Correlation Domain Analysis (BOCDA), which is a high spatial resolution distributed strain sensing system. This study began by investigating damage modes of CFRP bolted joints after bearing failure. Effective embedding positions of optical fibers were then proposed and their feasibility was evaluated by finite element analysis simulating the damage propagation in the bolted joint and consequent strain change. Finally, verification tests were conducted using specimens with embedded optical fibers at various positions. It was clearly shown that damage could be detected using residual strain due to fiber-microbuckling (kinking) damage or permanent deformation of neighboring plies. Furthermore, damage size and direction could be estimated from the change in the strain distribution. The system developed is quite useful for a first inspection of large-scale composite structures in aerospace applications.

Enhanced Comprehension of the Continuous Fusion Bonding Process of Multi-Material Structures

2018 ◽  
Vol 939 ◽  
pp. 197-204 ◽  
Author(s):  
Tobias Reincke ◽  
Sven Hartwig ◽  
Klaus Dilger
Keyword(s):  
Composite Structures ◽  
Large Scale ◽  
Lightweight Design ◽  
Continuous Process ◽  
Peel Test ◽  
Roll Forming ◽  
Scale Production ◽  
Continuous Manufacturing ◽  
Fusion Bonding ◽  
Reinforced Thermoplastics

In comparison to monolithic composite structures, tailored multi-material structures offer high potential considering lightweight design approaches in combination with cost efficient manufacturing processes. Roll forming enables flexible large scale production of hybrid structures, due to the continuous manufacturing process as well as high degree of automation. The multi-material structures consist of steel sheets which are selectively reinforced by unidirectional carbon fibre reinforced thermoplastics (CFR-TP). In view of minimizing process steps and decreasing cycle times, both materials are joined by fusion bonding. Therefore, CFR-TP is heated above melting temperature of thermoplastic matrix and joined to the steel surface under defined pressure and time. However, joining of both materials within a continuous process is still challenging due to a lack in terms of process comprehension. Consequently, multi-material specimens were manufactured depending on various process parameters as temperature of either material or processing speed and tested mechanically by floating roller peel test for the evaluation of the adhesion between both materials. Furthermore, viscosity of matrix was determined and investigations of CFR-TP interface were performed by Fourier transform infrared spectroscopy. The results show the requirement of a defined CFR-TP temperature and the change in crystalline structure of the matrix in dependency of the processing.

A Vision-Based Gap Detection Method during the Placement of Large-Scale Composite Structures

2011 ◽  
Vol 186 ◽  
pp. 11-15
Author(s):  
Li Cao ◽  
Wen Chen ◽  
Jun Xiao
Keyword(s):  
Image Processing ◽  
Video Processing ◽  
Composite Structures ◽  
Large Scale ◽  
Low Cost ◽  
High Quality ◽  
Detection Technology ◽  
Gap Measurement ◽  
Automatic Placement ◽  
On Line

Video processing technology is regarded as a low-cost detection technology in complex environment. Because the placement layer is thin and the surface is complex that causes high detection error and high cost in laser measurement. Two problems must be solved before using it in large-scale composite structures automatic placement. One is to obtain the high-quality and stable image, and the other is to improve efficiency of image processing. In this paper, a method obtaining the high quality placement gap images was studied. It made use of the optical characteristics of composite material’s surface texture. And some parameters were determined by experiments. To reduce the calculation cost of image processing, a placement gap measurement method based on line scanning was also proposed here. The method was effective in our detection experiments on an actual workpiece.

scholarly journals Convectively Coupled Kelvin Waves: From Linear Theory to Global Models

2015 ◽  
Vol 73 (1) ◽  
pp. 407-428 ◽  
Author(s):  
Michael J. Herman ◽  
Zeljka Fuchs ◽  
David J. Raymond ◽  
Peter Bechtold
Keyword(s):  
Composite Structures ◽  
Large Scale ◽  
Kelvin Waves ◽  
Radiosonde Data ◽  
3D Analysis ◽  
Kelvin Wave ◽  
Scale Characteristics ◽  
Precipitation Anomalies ◽  
Convective Inhibition ◽  
Ecmwf Model

Abstract The authors analyze composite structures of tropical convectively coupled Kelvin waves (CCKWs) in terms of the theory of Raymond and Fuchs using radiosonde data, 3D analysis and reanalysis model output, and annual integrations with the ECMWF model on the full planet and on an aquaplanet. Precipitation anomalies are estimated using the NOAA interpolated OLR and TRMM 3B42 datasets, as well as using model OLR and rainfall diagnostics. Derived variables from these datasets are used to examine assumptions of the theory. Large-scale characteristics of wave phenomena are robust in all datasets and models where Kelvin wave variance is large. Indices from the theory representing column moisture and convective inhibition are also robust. The results suggest that the CCKW is highly dependent on convective inhibition, while column moisture does not play an important role.

scholarly journals Preparation of Nickel Nanoparticles by Direct Current Arc Discharge Method and Their Catalytic Application in Hybrid Na-Air Battery

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 684 ◽  
Author(s):  
Fengmei Su ◽  
Xuechao Qiu ◽  
Feng Liang ◽  
Manabu Tanaka ◽  
Tao Qu ◽  
...  
Keyword(s):  
Direct Current ◽  
Composite Structures ◽  
High Speed ◽  
Large Scale ◽  
Nickel Nanoparticles ◽  
Arc Discharge ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Air Battery ◽  
Discharge Method

Nickel nanoparticles were prepared by the arc discharge method. Argon and argon/hydrogen mixtures were used as plasma gas; the evaporation of anode material chiefly resulted in the formation of different arc-anode attachments at different hydrogen concentrations. The concentration of hydrogen was fixed at 0, 30, and 50 vol% in argon arc, corresponding to diffuse, multiple, and constricted arc-anode attachments, respectively, which were observed by using a high-speed camera. The images of the cathode and anode jets were observed with a suitable band-pass filter. The relationship between the area change of the cathode/anode jet and the synchronous voltage/current waveform was studied. By investigating diverse arc-anode attachments, the effect of hydrogen concentration on the features of nickel nanoparticles were investigated, finding that 50 vol% H2 concentration has high productivity, fine crystallinity, and appropriate size distribution. The synthesized nickel nanoparticles were then used as catalysts in a hybrid sodium–air battery. Compared with commercial a silver nanoparticle catalyst and carbon black, nickel nanoparticles have better electrocatalytic performance. The promising electrocatalytic activity of nickel nanoparticles can be ascribed to their good crystallinity, effective activation sites, and Ni/NiO composite structures. Nickel nanoparticles prepared by the direct current (DC) arc discharge method have the potential to be applied as catalysts on a large scale.

Abstract WP313: Liposomes With Anti-Fibrin Protein Binders to Target Clot in Stroke

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Robert Mikulik ◽  
Hana Petroková ◽  
Josef Mašek ◽  
Milan Kuchar ◽  
Andrea Vítecková Wünschová ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Targeted Delivery ◽  
Animal Studies ◽  
Large Scale ◽  
Small Diameter ◽  
Titration Calorimetry ◽  
Ribosome Display ◽  
Main Challenge ◽  
Protein Binders

Introduction: Direct clot targeting represents attractive concept for clot imaging as well as targeted delivery of drugs, e.g. thrombolytics. Small protein binders attached to nanoliposomes may target thrombi and deliver drugs although selective affinity to fibrin and not fibrinogen is the main challenge. Methods: For identification and preparation of fibrin-specific artificial protein binders derived from scaffolds of albumin-binding domain (ABD) of streptococcal protein G, a highly complex ABD-derived combinatorial library in combination with ribosome display selection was used. In vitro models were used to document delivery of nanoliposomes to human thrombi. Results: A recombinant target as a stretch of three identical fibrin fragments of 16 amino acid peptides of the Bβ chain fused to TolA protein carrying polyhistidylated tag and Avitag was constructed. Ribosome display was followed by large-scale ELISA screening of protein binders. Only four protein variants had selective affinity to human fibrin - see figure 1A. The most selective, variant D7, was modified by C-terminal FLAG/His 6 or His 6 /His 6 tag in order to be attached onto the surface of nanoliposomes. The electron microscopy then confirmed the structure of nanoliposome-binder particles. Isothermal titration calorimetry provided dissociation constant for liposome-binder metallochelating bond in the range 10 -7 to 10 -9 for mono- and double-HisTag forms. In vitro, in silicone replica of small diameter artery, the confocal and scanning electron microscopy confirmed a successful binding of D7-attached- to-nanoliposomes to fibrin fibres, see figure 1B. Conclusions: We developed binders relatively selective to fibrin, attached them to nanoliposomes, and documented targeting of fibrin in vitro. As the next step, selectivity needs to be now documented in animal studies.

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